My sewing room improves any bad mood drastically, however, when I am in a bad mood, I do not quilt. I sort and pet my fabric, look for patterns, and do anything that I won't have to redo later. I've forced myself through some bad sewing times and the results were less than stellar. So I've learned not to cut or sew when I'm stressed, in a hurry, or upset.
I do notice a difference in the fabrics I pick depending on my mood.